Steroid Effects on Mucociliary Clearance in Outpatient Asthma

Abstract

Asthma, a chronic inflammatory condition of airways, responds to therapy with anti-inflammatory medications, for example, inhaled (ICS) and/or systemic (SS) corticosteroids. It is associated with impaired clearance of airway secretions. We studied effects of ICS and SS on mucociliary clearance (MC) in outpatient asthma through an in vivo, randomized, placebo-controlled single blind study with patients acting as their own control. Using a gamma camera and radiolabeled aerosol, we measured MC at baseline, after 4 days of nebulized treatment and after 5 days of oral prednisone. MC was expressed as percent of retained activity over time. Spirometry was performed before each MC study. Treatment with nebulized budesonide did not affect MC or forced expiratory volume at 1 sec (FEV1). Treatment with SS was associated with a significant improvement in MC at 24 h (baseline, 41 +/- 6; post-SS, 36 +/- 5; p = 0.04). Post hoc analysis revealed that MC changed only in those patients with significant changes in deposition (specific Central-to-Peripheral ratio C/P--baseline, 1.57 +/- 0.16; post-SS, 1.73 +/- 0.21; n = 6; p = 0.05), suggesting that the changes in MC were not directly related to therapy. In outpatient asthma, MC is unaffected by 4-5 days of anti-inflammatory therapy in spite of significant changes in FEV1.